alamillo: we haven't had a major rainstorm in the last year or so yet there's a lot of water in this creek here. i would say 20% of it is natural and the other 80% is runoff. shapiro: the purpose of the smurrf is to treat dry weather runoff, which is coming from storm drains. dry-weather runoff occurs when people waste water through washing their cars in the street, hosing down sidewalks and parking lots, their irrigation systems overspray. narrator: in a city of 12 million people, those seemingly small bits of wasted water accumulate to enormous amounts. shapiro: so all that ends up in our streets, ends up in catch basins, storm drains, into our storm drain system, and for some of the city, parts of the city, it ends up here at smurrf. 350,000 gallons come here on a daily basis, producing recycled water, and that can be reused for landscape irrigation and indoor toilet flushing.